1. Field of the Invention
The present invention relates end caps and similar closures that are used to seal the tops of containers and the open ends of pipes. More particularly, the present invention relates to the caps of pharmaceutical containers or pharmaceutical piping that are used in conjunction with a clamp to produce a hermetic seal around the opening of the container or pipe.
2. Description of the Prior Art
In the manufacture and processing of pharmaceutical products, dairy products and other materials that require a sanitary processing environment, it is common for materials transported in stainless steel containers. Once in a processing plant, pharmaceutical solutions are commonly pumped between points using a network of fixed pipes. To simplify processing, it is common for the containers and the pipes to have similarly shaped flanged openings. In this manner, containers can be readily joined to pipes and vise versa so that materials can be readily transferred between mobil containers and stationary piping.
Containers used in the pharmaceutical industry vary widely in shape size and volume. However, one common aspect of these containers is that they are commonly manufactured from stainless steel. In this manner, the containers can be sterilized in an autoclave if ever used to hold bio-hazardous or bio-active material.
Referring to FIG. 1, there is shown a prior art container 10 and a prior art end cap 12 for that container 10. The container 10 is of the STB-Series manufactured by Eagle Stainless Container of Horsham, Pa. The shown container 10 serves to exemplify containers commonly used to transport samples in the pharmaceutical industry. As can be seen from FIG. 1, the container 10 has a radial flange 14 disposed around the open top end 16 of the container 10. A groove 18 is disposed on the top surface 16 of the flange 14, wherein the groove 18 is shaped to retain part of a gasket 20. The bottom surface 22 of the flange 14 is angled, thereby providing the flange 14 with a tapered shape.
The end cap 12 shown typifies the type of cap currently used to seal pharmaceutical containers and pharmaceutical piping. The end cap 12 is a solid disk of stainless steel. A groove 24 is formed on the bottom surface of the end cap 12. The groove 24 on the end cap 12 aligns with the groove 18 on the flange 14 of the container 10. A section 26 of the top surface of the cap near the peripheral edge is beveled at the same angle as is the bottom surface 22 of the flange 14 on the container 10.
A gasket 20 is placed between the end cap 12 and the container 10. The gasket 20 fits within the grooves 24, 18 on the bottom of the end cap 12 and the top of the container 10, respectively. A pipe clamp (not shown) is then used to bias the end cap 12 against the container 10. Such pipe clamps are exemplified by U.S. Pat. No. 4,568,115 to Zimmerly, entitled Multi-Piece Pipe Clamp. The pipe clamp compresses the gasket 20 between the end cap 12 and the container 10, thereby making a hermetic seal. Since neither, the container 10 nor the end cap 12 contain threads, there are few places for contaminants to hide. Accordingly, both elements are readily cleaned and sterilized using a laboratory autoclave.
When a sample of material is sealed into a container, the material may then cool or change chemically over time. Similarly, the ambient air temperature may rise above that at the time the container was sealed. Both scenarios can cause the pressure within the sealed container to be less than ambient air pressure. As a result, a vapor lock occurs wherein the differential between internal and external air pressure causes end cap to remain set in place even after the pipe clamp is removed. In such situations a person must often pry the end cap off of the container using a screw driver or other tool. This requires a tool be at hand and also consume a great amount of time and effort. Furthermore, the prying procedure can cause damage to the container, the end cap, the gasket or can cause the contents of the container to spill.
End caps, such as that described, are also used to seal the ends of pipes in a pharmaceutical processing plant. In such situations, the end of the pipe may be elevated or at some other point that is hard to reach. If the end cap is pried off of the end of the pipe and is not caught, the end cap often falls to the ground. Since the end cap is solid stainless steel, it can easily injure a person, cause damage to some equipment it strikes or incur damage itself when striking another object.
In the prior art of lids and closures, there are many different lids that include protrusions so that those lids need not be pried from atop a container. Such prior art lids are exemplified by U.S. Pat. No. 1,437,572 to Vons, entitled Bottle Stopper and U.S. Pat. No. 742,652 to Hirst, entitled Jar or Bottle Closure. Such lid projections provide a small amount of leverage to remove a lid. However, such protrusions are not sufficient enough to enable a person to remove a solid stainless steel end cap from a vapor locked pipe or container in a controlled manner.
A need therefore exists for an end cap for a pharmaceutical container or pipe that can be removed from a vapor locked application without a tool and can be removed in a controlled manner without fear of the end cap falling or otherwise being dropped. Such a need is met by the present invention as described and claimed below.